Trading orders with decaying reserves

ABSTRACT

In various embodiments, an apparatus includes a processor and a memory. The memory is communicatively coupled to the processor. The memory stores software instructions that, when executed by the processor, cause the processor to receive a trading order for a particular quantity of a trading product. The trading order specifies that a first portion of the particular quantity is a displayed quantity and that a second portion of the particular quantity is a reserved quantity. The trading order specifies at least one of a decay rule, a decay interval, a decay rate, decay quantity, and one or more conditions. The software instructions, when executed by the processor, cause the processor to cause the reserved quantity to decay based at least in part on at least one of the decay rule, the decay interval, the decay rate, and the decay quantity, and one or more conditions.

CROSS REFERENCE TO RELATED APPLICATION

This patent application is a continuation-in-part application of U.S.patent application Ser. No. 12/106,494, filed Apr. 21, 2008, which ishereby incorporated by reference herein in its entirety.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a system according to at least one embodiment of thesystems disclosed herein.

FIG. 2 illustrates decay of a trading order with a reserved quantity,according to certain embodiments.

FIG. 3 illustrates decay of a trading order with a reserved quantity,according to certain embodiments.

FIG. 4 illustrates a flowchart for managing a trading order with areserved quantity, according to certain embodiments.

DETAILED DESCRIPTION

The following sections I-X provide a guide to interpreting the presentapplication.

I. Terms

The term “product” means any machine, manufacture and/or composition ofmatter, unless expressly specified otherwise.

The term “process” means any process, algorithm, method or the like,unless expressly specified otherwise.

Each process (whether called a method, algorithm or otherwise)inherently includes one or more steps, and therefore all references to a“step” or “steps” of a process have an inherent antecedent basis in themere recitation of the term ‘process’ or a like term. Accordingly, anyreference in a claim to a ‘step’ or ‘steps’ of a process has sufficientantecedent basis.

The term “invention” and the like mean “the one or more inventionsdisclosed in this application”, unless expressly specified otherwise.

The terms “an embodiment”, “embodiment”, “embodiments”, “theembodiment”, “the embodiments”, “one or more embodiments”, “someembodiments”, “certain embodiments”, “one embodiment”, “anotherembodiment” and the like mean “one or more (but not all) embodiments ofthe disclosed invention(s)”, unless expressly specified otherwise.

The term “variation” of an invention means an embodiment of theinvention, unless expressly specified otherwise.

A reference to “another embodiment” in describing an embodiment does notimply that the referenced embodiment is mutually exclusive with anotherembodiment (e.g., an embodiment described before the referencedembodiment), unless expressly specified otherwise.

The terms “including”, “comprising” and variations thereof mean“including but not necessarily limited to”, unless expressly specifiedotherwise. Thus, for example, the sentence “the portfolio includes a redwidget and a blue widget” means the portfolio includes the red widgetand the blue widget, but may include something else.

The term “consisting of” and variations thereof means “including andlimited to”, unless expressly specified otherwise. Thus, for example,the sentence “the portfolio consists of a red widget and a blue widget”means the portfolio includes the red widget and the blue widget, butdoes not include anything else.

The term “compose” and variations thereof means “to make up theconstituent parts of, component of or member of”, unless expresslyspecified otherwise. Thus, for example, the sentence “the red widget andthe blue widget compose a portfolio” means the portfolio includes thered widget and the blue widget.

The term “exclusively compose” and variations thereof means “to make upexclusively the constituent parts of, to be the only components of or tobe the only members of”, unless expressly specified otherwise. Thus, forexample, the sentence “the red widget and the blue widget exclusivelycompose a portfolio” means the portfolio consists of the red widget andthe blue widget, and nothing else.

The terms “a”, “an” and “the” mean “one or more”, unless expresslyspecified otherwise.

The term “plurality” means “two or more”, unless expressly specifiedotherwise.

The term “herein” means “in the present application, including anythingwhich may be incorporated by reference”, unless expressly specifiedotherwise.

The phrase “at least one of”, when such phrase modifies a plurality ofthings (such as an enumerated list of things) means any combination ofone or more of those things, unless expressly specified otherwise. Forexample, the phrase “at least one of a widget, a car and a wheel” meanseither (i) a widget, (ii) a car, (iii) a wheel, (iv) a widget and a car,(v) a widget and a wheel, (vi) a car and a wheel, or (vii) a widget, acar and a wheel. The phrase “at least one of”, when such phrase modifiesa plurality of things does not mean “one of each of” the plurality ofthings.

Numerical terms such as “one”, “two”, etc. when used as cardinal numbersto indicate quantity of something (e.g., one widget, two widgets), meanthe quantity indicated by that numerical term, but do not mean at leastthe quantity indicated by that numerical term. For example, the phrase“one widget” does not mean “at least one widget”, and therefore thephrase “one widget” does not cover, e.g., two widgets.

The phrase “based on” does not mean “based only on”, unless expresslyspecified otherwise. In other words, the phrase “based on” describesboth “based only on” and “based at least on”. The phrase “based at leaston” is equivalent to the phrase “based at least in part on”.

The term “represent” and like terms are not exclusive, unless expresslyspecified otherwise. For example, the term “represents” does not mean“represents only”, unless expressly specified otherwise. In other words,the phrase “the data represents a credit card number” describes both“the data represents only a credit card number” and “the data representsa credit card number and the data also represents something else”.

The term “whereby” is used herein only to precede a clause or other setof words that express only the intended result, objective or consequenceof something that is previously and explicitly recited. Thus, when theterm “whereby” is used in a claim, the clause or other words that theterm “whereby” modifies do not establish specific further limitations ofthe claim or otherwise restricts the meaning or scope of the claim.

The term “e.g.” and like terms mean “for example”, and thus does notlimit the term or phrase it explains. For example, in the sentence “thecomputer sends data (e.g., instructions, a data structure) over theInternet”, the term “e.g.” explains that “instructions” are an exampleof “data” that the computer may send over the Internet, and alsoexplains that “a data structure” is an example of “data” that thecomputer may send over the Internet. However, both “instructions” and “adata structure” are merely examples of “data”, and other things besides“instructions” and “a data structure” can be “data”.

The term “respective” and like terms mean “taken individually”. Thus iftwo or more things have “respective” characteristics, then each suchthing has its own characteristic, and these characteristics can bedifferent from each other but need not be. For example, the phrase “eachof two machines has a respective function” means that the first suchmachine has a function and the second such machine has a function aswell. The function of the first machine may or may not be the same asthe function of the second machine.

The term “i.e.” and like terms mean “that is”, and thus limits the termor phrase it explains. For example, in the sentence “the computer sendsdata (i.e., instructions) over the Internet”, the term “i.e.” explainsthat “instructions” are the “data” that the computer sends over theInternet.

Any given numerical range shall include whole and fractions of numberswithin the range. For example, the range “1 to 10” shall be interpretedto specifically include whole numbers between 1 and 10 (e.g., 1, 2, 3,4, . . . 9) and non-whole numbers (e.g., 1.1, 1.2, . . . 1.9).

Where two or more terms or phrases are synonymous (e.g., because of anexplicit statement that the terms or phrases are synonymous), instancesof one such term/phrase does not mean instances of another suchterm/phrase must have a different meaning. For example, where astatement renders the meaning of “including” to be synonymous with“including but not limited to”, the mere usage of the phrase “includingbut not limited to” does not mean that the term “including” meanssomething other than “including but not limited to”.

II. Determining

The term “determining” and grammatical variants thereof (e.g., todetermine a price, determining a value, determine an object which meetsa certain criterion) is used in an extremely broad sense. The term“determining” encompasses a wide variety of actions and therefore“determining” can include calculating, computing, processing, deriving,investigating, looking up (e.g., looking up in a table, a database oranother data structure), ascertaining and the like. Also, “determining”can include receiving (e.g., receiving information), accessing (e.g.,accessing data in a memory) and the like. Also, “determining” caninclude resolving, selecting, choosing, establishing, and the like.

The term “determining” does not imply certainty or absolute precision,and therefore “determining” can include estimating, extrapolating,predicting, guessing and the like.

The term “determining” does not imply that mathematical processing mustbe performed, and does not imply that numerical methods must be used,and does not imply that an algorithm or process is used.

The term “determining” does not imply that any particular device must beused. For example, a computer need not necessarily perform thedetermining.

III. Forms of Sentences

Where a limitation of a first claim would cover one of a feature as wellas more than one of a feature (e.g., a limitation such as “at least onewidget” covers one widget as well as more than one widget), and where ina second claim that depends on the first claim, the second claim uses adefinite article “the” to refer to the limitation (e.g., “the widget”),this does not imply that the first claim covers only one of the feature,and this does not imply that the second claim covers only one of thefeature (e.g., “the widget” can cover both one widget and more than onewidget).

When an ordinal number (such as “first”, “second”, “third” and so on) isused as an adjective before a term, that ordinal number is used (unlessexpressly specified otherwise) merely to indicate a particular feature,such as to distinguish that particular feature from another feature thatis described by the same term or by a similar term. For example, a“first widget” may be so named merely to distinguish it from, e.g., a“second widget”. Thus, the mere usage of the ordinal numbers “first” and“second” before the term “widget” does not indicate any otherrelationship between the two widgets, and likewise does not indicate anyother characteristics of either or both widgets. For example, the mereusage of the ordinal numbers “first” and “second” before the term“widget” (1) does not indicate that either widget comes before or afterany other in order or location; (2) does not indicate that either widgetoccurs or acts before or after any other in time; and (3) does notindicate that either widget ranks above or below any other, as inimportance or quality. In addition, the mere usage of ordinal numbersdoes not define a numerical limit to the features identified with theordinal numbers. For example, the mere usage of the ordinal numbers“first” and “second” before the term “widget” does not indicate thatthere must be no more than two widgets.

When a single device, article or other product is described herein, morethan one device/article (whether or not they cooperate) mayalternatively be used in place of the single device/article that isdescribed. Accordingly, the functionality that is described as beingpossessed by a device may alternatively be possessed by more than onedevice/article (whether or not they cooperate).

Similarly, where more than one device, article or other product isdescribed herein (whether or not they cooperate), a singledevice/article may alternatively be used in place of the more than onedevice or article that is described. For example, a plurality ofcomputer-based devices may be substituted with a single computer-baseddevice. Accordingly, the various functionality that is described asbeing possessed by more than one device or article may alternatively bepossessed by a single device/article.

The functionality and/or the features of a single device that isdescribed may be alternatively embodied by one or more other deviceswhich are described but are not explicitly described as having suchfunctionality/features. Thus, other embodiments need not include thedescribed device itself, but rather can include the one or more otherdevices which would, in those other embodiments, have suchfunctionality/features.

IV. Disclosed Examples and Terminology are Not Limiting

Neither the Title (set forth at the beginning of the first page of thepresent application) nor the Abstract (set forth at the end of thepresent application) is to be taken as limiting in any way as the scopeof the disclosed invention(s), is to be used in interpreting the meaningof any claim or is to be used in limiting the scope of any claim. AnAbstract has been included in this application merely because anAbstract is required under 37 C.F.R. §1.72(b).

The title of the present application and headings of sections providedin the present application are for convenience only, and are not to betaken as limiting the disclosure in any way.

Numerous embodiments are described in the present application, and arepresented for illustrative purposes only. The described embodiments arenot, and are not intended to be, limiting in any sense. The presentlydisclosed invention(s) are widely applicable to numerous embodiments, asis readily apparent from the disclosure. One of ordinary skill in theart will recognize that the disclosed invention(s) may be practiced withvarious modifications and alterations, such as structural, logical,software, and electrical modifications. Although particular features ofthe disclosed invention(s) may be described with reference to one ormore particular embodiments and/or drawings, it should be understoodthat such features are not limited to usage in the one or moreparticular embodiments or drawings with reference to which they aredescribed, unless expressly specified otherwise.

Though an embodiment may be disclosed as including several features,other embodiments of the invention may include fewer than all suchfeatures. Thus, for example, a claim may be directed to less than theentire set of features in a disclosed embodiment, and such claim wouldnot include features beyond those features that the claim expresslyrecites.

No embodiment of method steps or product elements described in thepresent application constitutes the invention claimed herein, or isessential to the invention claimed herein, or is coextensive with theinvention claimed herein, except where it is either expressly stated tobe so in this specification or expressly recited in a claim.

The preambles of the claims that follow recite purposes, benefits andpossible uses of the claimed invention only and do not limit the claimedinvention.

The present disclosure is not a literal description of all embodimentsof the invention(s). Also, the present disclosure is not a listing offeatures of the invention(s) which must be present in all embodiments.

All disclosed embodiments are not necessarily covered by the claims(even including all pending, amended, issued and canceled claims). Inaddition, an embodiment may be (but need not necessarily be) covered byseveral claims. Accordingly, where a claim (regardless of whetherpending, amended, issued or canceled) is directed to a particularembodiment, such is not evidence that the scope of other claims do notalso cover that embodiment.

Devices that are described as in communication with each other need notbe in continuous communication with each other, unless expresslyspecified otherwise. On the contrary, such devices need only transmit toeach other as necessary or desirable, and may actually refrain fromexchanging data most of the time. For example, a machine incommunication with another machine via the Internet may not transmitdata to the other machine for long period of time (e.g. weeks at atime). In addition, devices that are in communication with each othermay communicate directly or indirectly through one or moreintermediaries.

A description of an embodiment with several components or features doesnot imply that all or even any of such components/features are required.On the contrary, a variety of optional components are described toillustrate the wide variety of possible embodiments of the presentinvention(s). Unless otherwise specified explicitly, nocomponent/feature is essential or required.

Although process steps, algorithms or the like may be described orclaimed in a particular sequential order, such processes may beconfigured to work in different orders. In other words, any sequence ororder of steps that may be explicitly described or claimed does notnecessarily indicate a requirement that the steps be performed in thatorder. The steps of processes described herein may be performed in anyorder possible. Further, some steps may be performed simultaneouslydespite being described or implied as occurring non-simultaneously(e.g., because one step is described after the other step). Moreover,the illustration of a process by its depiction in a drawing does notimply that the illustrated process is exclusive of other variations andmodifications thereto, does not imply that the illustrated process orany of its steps are necessary to the invention(s), and does not implythat the illustrated process is preferred.

Although a process may be described as including a plurality of steps,that does not imply that all or any of the steps are preferred,essential or required. Various other embodiments within the scope of thedescribed invention(s) include other processes that omit some or all ofthe described steps. Unless otherwise specified explicitly, no step isessential or required.

Although a process may be described singly or without reference to otherproducts or methods, in an embodiment the process may interact withother products or methods. For example, such interaction may includelinking one business model to another business model. Such interactionmay be provided to enhance the flexibility or desirability of theprocess.

Although a product may be described as including a plurality ofcomponents, aspects, qualities, characteristics and/or features, thatdoes not indicate that any or all of the plurality are preferred,essential or required. Various other embodiments within the scope of thedescribed invention(s) include other products that omit some or all ofthe described plurality.

An enumerated list of items (which may or may not be numbered) does notimply that any or all of the items are mutually exclusive, unlessexpressly specified otherwise. Likewise, an enumerated list of items(which may or may not be numbered) does not imply that any or all of theitems are comprehensive of any category, unless expressly specifiedotherwise. For example, the enumerated list “a computer, a laptop, aPDA” does not imply that any or all of the three items of that list aremutually exclusive and does not imply that any or all of the three itemsof that list are comprehensive of any category.

An enumerated list of items (which may or may not be numbered) does notimply that any or all of the items are equivalent to each other orreadily substituted for each other.

All embodiments are illustrative, and do not imply that the invention orany embodiments were made or performed, as the case may be.

V. Computing

It will be readily apparent to one of ordinary skill in the art that thevarious processes described herein may be implemented by, e.g.,appropriately programmed general purpose computers, special purposecomputers and computing devices. Typically a processor (e.g., one ormore microprocessors, one or more microcontrollers, one or more digitalsignal processors) will receive instructions (e.g., from a memory orlike device), and execute those instructions, thereby performing one ormore processes defined by those instructions. Instructions may beembodied in, e.g., one or more computer programs, one or more scripts.

A “processor” means one or more microprocessors, central processingunits (CPUs), computing devices, microcontrollers, digital signalprocessors, or like devices or any combination thereof, regardless ofthe architecture (e.g., chip-level multiprocessing/multi-core, RISC,CISC, Microprocessor without Interlocked Pipeline Stages, pipeliningconfiguration, simultaneous multithreading).

Thus a description of a process is likewise a description of anapparatus for performing the process. The apparatus that performs theprocess can include, e.g., a processor and those input devices andoutput devices that are appropriate to perform the process.

Further, programs that implement such methods (as well as other types ofdata) may be stored and transmitted using a variety of media (e.g.,computer readable media) in a number of manners. In some embodiments,hard-wired circuitry or custom hardware may be used in place of, or incombination with, some or all of the software instructions that canimplement the processes of various embodiments. Thus, variouscombinations of hardware and software may be used instead of softwareonly.

The term “computer-readable medium” refers to any medium, a plurality ofthe same, or a combination of different media, that participate inproviding data (e.g., instructions, data structures) which may be readby a computer, a processor or a like device. Such a medium may take manyforms, including but not limited to, non-volatile media, volatile media,and transmission media. Non-volatile media include, for example, opticalor magnetic disks and other persistent memory. Volatile media includedynamic random access memory (DRAM), which typically constitutes themain memory. Transmission media include coaxial cables, copper wire andfiber optics, including the wires that comprise a system bus coupled tothe processor. Transmission media may include or convey acoustic waves,light waves and electromagnetic emissions, such as those generatedduring radio frequency (RF) and infrared (IR) data communications.Common forms of computer-readable media include, for example, a floppydisk, a flexible disk, hard disk, magnetic tape, any other magneticmedium, a CD-ROM, DVD, any other optical medium, punch cards, papertape, any other physical medium with patterns of holes, a RAM, a PROM,an EPROM, a FLASH-EEPROM, any other memory chip or cartridge, a carrierwave as described hereinafter, or any other medium from which a computercan read.

Various forms of computer readable media may be involved in carryingdata (e.g. sequences of instructions) to a processor. For example, datamay be (i) delivered from RAM to a processor; (ii) carried over awireless transmission medium; (iii) formatted and/or transmittedaccording to numerous formats, standards or protocols, such as Ethernet(or IEEE 802.3), SAP, ATP, Bluetooth□, and TCP/IP, TDMA, CDMA, and 3G;and/or (iv) encrypted to ensure privacy or prevent fraud in any of avariety of ways well known in the art.

Thus a description of a process is likewise a description of acomputer-readable medium storing a program for performing the process.The computer-readable medium can store (in any appropriate format) thoseprogram elements which are appropriate to perform the method.

Just as the description of various steps in a process does not indicatethat all the described steps are required, embodiments of an apparatusinclude a computer/computing device operable to perform some (but notnecessarily all) of the described process.

Likewise, just as the description of various steps in a process does notindicate that all the described steps are required, embodiments of acomputer-readable medium storing a program or data structure include acomputer-readable medium storing a program that, when executed, cancause a processor to perform some (but not necessarily all) of thedescribed process.

Where databases are described, it will be understood by one of ordinaryskill in the art that (i) alternative database structures to thosedescribed may be readily employed, and (ii) other memory structuresbesides databases may be readily employed. Any illustrations ordescriptions of any sample databases presented herein are illustrativearrangements for stored representations of information. Any number ofother arrangements may be employed besides those suggested by, e.g.,tables illustrated in drawings or elsewhere. Similarly, any illustratedentries of the databases represent exemplary information only; one ofordinary skill in the art will understand that the number and content ofthe entries can be different from those described herein. Further,despite any depiction of the databases as tables, other formats(including relational databases, object-based models and/or distributeddatabases) could be used to store and manipulate the data typesdescribed herein. Likewise, object methods or behaviors of a databasecan be used to implement various processes, such as the describedherein. In addition, the databases may, in a known manner, be storedlocally or remotely from a device which accesses data in such adatabase.

Various embodiments can be configured to work in a network environmentincluding a computer that is in communication (e.g., via acommunications network) with one or more devices. The computer maycommunicate with the devices directly or indirectly, via any wired orwireless medium (e.g. the Internet, LAN, WAN or Ethernet, Token Ring, atelephone line, a cable line, a radio channel, an optical communicationsline, commercial on-line service providers, bulletin board systems, asatellite communications link, a combination of any of the above). Eachof the devices may themselves comprise computers or other computingdevices, such as those based on the Intel® Pentium® or Centrino™processor, that are adapted to communicate with the computer. Any numberand type of devices may be in communication with the computer.

In an embodiment, a server computer or centralized authority may not benecessary or desirable. For example, the present invention may, in anembodiment, be practiced on one or more devices without a centralauthority. In such an embodiment, any functions described herein asperformed by the server computer or data described as stored on theserver computer may instead be performed by or stored on one or moresuch devices.

Where a process is described, in an embodiment the process may operatewithout any user intervention. In another embodiment, the processincludes some human intervention (e.g., a step is performed by or withthe assistance of a human).

VI. Continuing Applications

The present disclosure provides, to one of ordinary skill in the art, anenabling description of several embodiments and/or inventions. Some ofthese embodiments and/or inventions may not be claimed in the presentapplication, but may nevertheless be claimed in one or more continuingapplications that claim the benefit of priority of the presentapplication.

Applicants intend to file additional applications to pursue patents forsubject matter that has been disclosed and enabled but not claimed inthe present application.

VII. 35 U.S.C. §112, paragraph 6

In a claim, a limitation of the claim which includes the phrase “meansfor” or the phrase “step for” means that 35 U.S.C. §112, paragraph 6,applies to that limitation.

In a claim, a limitation of the claim which does not include the phrase“means for” or the phrase “step for” means that 35 U.S.C. §112,paragraph 6 does not apply to that limitation, regardless of whetherthat limitation recites a function without recitation of structure,material or acts for performing that function. For example, in a claim,the mere use of the phrase “step of” or the phrase “steps of” inreferring to one or more steps of the claim or of another claim does notmean that 35 U.S.C. §112, paragraph 6, applies to that step(s).

With respect to a means or a step for performing a specified function inaccordance with 35 U.S.C. §112, paragraph 6, the correspondingstructure, material or acts described in the specification, andequivalents thereof, may perform additional functions as well as thespecified function.

Computers, processors, computing devices and like products arestructures that can perform a wide variety of functions. Such productscan be operable to perform a specified function by executing one or moreprograms, such as a program stored in a memory device of that product orin a memory device which that product accesses. Unless expresslyspecified otherwise, such a program need not be based on any particularalgorithm, such as any particular algorithm that might be disclosed inthe present application. It is well known to one of ordinary skill inthe art that a specified function may be implemented via differentalgorithms, and any of a number of different algorithms would be a meredesign choice for carrying out the specified function.

Therefore, with respect to a means or a step for performing a specifiedfunction in accordance with 35 U.S.C. §112, paragraph 6, structurecorresponding to a specified function includes any product programmed toperform the specified function. Such structure includes programmedproducts which perform the function, regardless of whether such productis programmed with (i) a disclosed algorithm for performing thefunction, (ii) an algorithm that is similar to a disclosed algorithm, or(iii) a different algorithm for performing the function.

Where there is recited a means for performing a function that is amethod, one structure for performing this method includes a computingdevice (e.g., a general purpose computer) that is programmed and/orconfigured with appropriate hardware to perform that function.

Also included is a computing device (e.g., a general purpose computer)that is programmed and/or configured with appropriate hardware toperform that function via other algorithms as would be understood by oneof ordinary skill in the art.

VIII. Disclaimer

Numerous references to a particular embodiment do not indicate adisclaimer or disavowal of additional, different embodiments, andsimilarly references to the description of embodiments which all includea particular feature do not indicate a disclaimer or disavowal ofembodiments which do not include that particular feature. A cleardisclaimer or disavowal in the present application shall be prefaced bythe phrase “does not include” or by the phrase “cannot perform”.

IX. Incorporation by Reference

Any patent, patent application or other document referred to herein isincorporated by reference into this patent application as part of thepresent disclosure, but only for purposes of written description andenablement in accordance with 35 U.S.C. §112, paragraph 1, and should inno way be used to limit, define, or otherwise construe any term of thepresent application, unless without such incorporation by reference, noordinary meaning would have been ascertainable by a person of ordinaryskill in the art. Such person of ordinary skill in the art need not havebeen in any way limited by any embodiments provided in the reference

Any incorporation by reference does not, in and of itself, imply anyendorsement of, ratification of or acquiescence in any statements,opinions, arguments or characterizations contained in any incorporatedpatent, patent application or other document, unless explicitlyspecified otherwise in this patent application.

X. Prosecution History

In interpreting the present application (which includes the claims), oneof ordinary skill in the art shall refer to the prosecution history ofthe present application, but not to the prosecution history of any otherpatent or patent application, regardless of whether there are otherpatent applications that are considered related to the presentapplication, and regardless of whether there are other patentapplications that share a claim of priority with the presentapplication.

In recent years, electronic trading systems have gained wide spreadacceptance for trading of a wide variety of items, such as goods,services, financial instruments, and commodities. For example,electronic trading systems have been created which facilitate thetrading of financial instruments and commodities such as stocks, bonds,currency, futures contracts, oil, and gold.

Many of these electronic trading systems use a bid/offer process inwhich bids and offers are submitted to the systems by a passive side andthen those bids and offers are hit or lifted (or taken) by an aggressiveside. For example, a passive trading counterparty may submit a “bid” tobuy a particular trading product. In response to such a bid, anaggressive side counterparty may submit a “hit” in order to indicate awillingness to sell the trading product to the first counterparty at thegiven price. Alternatively, a passive side counterparty may submit an“offer” to sell the particular trading product at the given price, andthen the aggressive side counterparty may submit a “lift” (or “take”) inresponse to the offer to indicate a willingness to buy the tradingproduct from the passive side counterparty at the given price.

In some embodiments, a system comprises a memory operable to store atrading order for a particular quantity of a trading product, wherein afirst portion of the particular quantity is a displayed quantity and asecond portion of the particular quantity is a reserved quantity. Thesystem further comprises a processor communicatively coupled to thememory and operable to disclose the displayed quantity to one or moremarket centers. The processor is further operable to identify a decayrate associated with the trading order. The processor is furtheroperable to cause the reserved quantity to decay based at least in parton the identified decay rate.

Various embodiments of the present disclosure may benefit from numerousadvantages. It should be noted that one or more embodiments may benefitfrom some, none, or all of the advantages discussed below.

One advantage is that a trading system may allow a trader to submit atrading order comprising a displayed quantity and a reserved quantity.The trading system may disclose the displayed quantity to multiplemarket centers while preventing the disclosure of the reserved quantity.In some embodiment, the trading system causes the reserved quantity ofthe trading order to decay over time. The trading system may therebyreduce certain risks associated with market volatility. In particular,by causing the reserved quantity to decay, the trading system may reducethe trader's risk of having exposure for a stale trading order with aprice that is no longer favorable for the trader.

Another advantage is that, by causing the reserved quantity of tradingorder to decay, the trading system may improve system efficiency. Inparticular, as trading orders with reserved quantities are notaggressed, trading system may gradually delete the reserved quantitiesof such trading orders from one or more order books. Deleting portionsof such trading orders may free up memory and processing resources inthe trading system. Trading system may thereby improve data throughputand/or conserve system resources.

A system comprises a memory operable to store a trading order for aparticular quantity of a trading product, wherein a first portion of theparticular quantity is a displayed quantity and a second portion of theparticular quantity is a reserved quantity. The system further comprisesa processor communicatively coupled to the memory and operable todisclose the displayed quantity to one or more market centers. Theprocessor is further operable to identify a decay rate associated withthe trading order. The processor is further operable to cause thereserved quantity to decay based at least in part on the identifieddecay rate.

FIG. 1 illustrates one embodiment of a trading system 10. Generally,trading system 10 comprises a trading platform 50 communicativelycoupled to clients 20, networks 30, and market centers 40. Tradingplatform 50 may receive and process trading orders 12 from traders 70.In some embodiments, trading platform 50 may cause a portion of tradingorder 12 to decay over time. Trading platform 50 may thereby reducecertain risks associated with market volatility. In particular, bycausing a portion of trading order 12 to decay, trading platform 50 mayreduce the risks of having exposure to a stale trading order 12 with aprice that has become unfavorable.

A given trading order 12 may comprise two parts—a “displayed quantity”and a “reserved quantity.” In placing trading order 12, trader 70 mayindicate that only a portion of the total quantity of trading order 12should be displayed to other traders 70. This portion of trading order12 to be displayed to other traders 70 is referred to as the “displayedquantity.” The remaining portion of trading order 12 is referred to asthe “reserved quantity.” Designating a portion of trading order 12 as a“reserved quantity” allows trader 70 to enter a large trading order 12while only displaying a portion of that trading order 12 to othertraders 70. Trading platform 50 may incrementally fill a particulartrading order 12 by first filling the displayed quantity of that tradingorder 12 and then using the reserved quantity to replenish the displayedquantity of that trading order 12.

Trading orders 12 generally comprise orders 12 a and counterorders 12 b.Orders 12 a and counterorders 12 b may be buy orders 14 and sell orders16. Orders 12 a and counterorders 12 b are complementary actions suchas, for example, buying and selling. If an order 12 a refers to a buyorder 14, then a counterorder 12 b refers to a sell order 16.Conversely, if an order 12 a refers to a sell order 16, then acounterorder 12 b refers to a buy order 14. A buy order 14 is a requestto buy a particular quantity of a particular trading product (e.g., bidrequest). A sell order 16 is a request to sell a particular quantity ofa particular trading product (e.g., offer request). In particularembodiments, trading order 12 may specify a target price (e.g., targetbid price or target offer price) for the trading product. Althoughsystem 10 is exemplified below using equities as the trading product,the trading product that forms the basis of trading order 12 maycomprise any type of goods, services, financial instruments,commodities, any other suitable product or combination of products.Examples of financial instruments include, but are not limited to,stocks, bonds, futures contracts, fixed income securities, interest ratederivatives, currencies, debentures, options, securities, derivativetrading instruments, etc.

Clients 20 are operable to receive trading orders 12 from traders 70 andto send trading orders 12 to trading platform 50 and/or market centers40. Clients 20 comprise any suitable local or remote end-user devicesthat may be used by traders 70 to access one or more elements of tradingsystem 10, such as trading platform 50. A particular client 20 maycomprise a computer, workstation, telephone, Internet browser,electronic notebook, Personal Digital Assistant (PDA), pager, or anyother suitable device (wireless or otherwise), component, or elementcapable of receiving, processing, storing, and/or communicatinginformation with other components of system 10. Client 20 may alsocomprise any suitable user interface such as a display, microphone,keypad, keyboard, touch screen, or any other appropriate terminalequipment according to particular configurations and arrangements. Itwill be understood that there may be any number of clients 20communicatively connected to trading platform 50. In addition, there maybe any number of clients 20 communicatively connected to market centers40 without using trading platform 50.

Although clients 20 are described herein as being used by “traders” 70,it should be understood that the term “trader” is meant to broadly applyto any user of trading system 10, whether that user is an agent actingon behalf of a principal, a principal, an individual, a legal entity(such as a corporation), or any machine or mechanism that is capable ofplacing and/or responding to trading orders 12 in system 10.

According to certain embodiments, traders 70 may include market makers.A market maker may include any individual or firm that submits and/ormaintains either or both bid and offer trading orders 12 simultaneouslyfor the same instrument. For example, a market maker may include anindividual or firm, such as a brokerage or bank, that maintains either afirm bid and/or offer price in a given security by standing ready,willing, and able to buy and/or sell that security at publicly quotedprices. A market maker generally displays bid and/or offer prices forspecific numbers of specific securities, and if these prices are met,the market maker will immediately buy for and/or sell from its ownaccounts. According to certain embodiments, a single trading order 12may be filled by a number of market makers at potentially differentprices.

Networks 30 are communication platforms operable to exchange data orinformation between clients 20 and trading platform 50 and/or marketcenters 40. According to certain embodiments, a particular network 30may represent an Internet architecture which provides clients 20 withthe ability to communicate trading or transaction information to tradingplatform 50 and/or market centers 40. According to certain embodiments,network 30 comprises a plain old telephone system (POTS), which traders70 may use to perform the same operations and functions. Transactionsmay be assisted by a broker associated with trading platform 50 ormanually keyed into a telephone or other suitable electronic device torequest that a transaction be executed. In certain embodiments, network30 may be any packet data network (PDN) offering a communicationsinterface or exchange between any two nodes in system 10. Network 30 maycomprise any combination of local area network (LAN), metropolitan areanetwork (MAN), wide area network (WAN), wireless local area network(WLAN), virtual private network (VPN), intranet, or any otherappropriate architecture or system that facilitates communicationsbetween clients 20 and trading platform 50 and/or market centers 40.

Market centers 40 comprise all manner of order execution venuesincluding exchanges, Electronic Communication Networks (ECNs),Alternative Trading Systems (ATSs), market makers, or any other suitablemarket participants. Each market center 40 maintains a bid and offerprice for a given trading product by standing ready, willing, and ableto buy or sell that trading product at publicly quoted prices, alsoreferred to as market center prices. Different market centers 40 mayprovide different market center prices for particular trading products.For example, a particular market center 40 may offer a particular bidprice and/or offer price for a particular trading product, while anothermarket center 40 may offer a different bid price and/or offer price forthe same trading product. A particular market center 40 may charge atransaction cost to execute trading orders 12 that remain in the orderbooks of that market center 40 for more than a certain length of time.Different market centers 40 may have different policies regarding thedisclosure of various details of trading orders 12. For example, certainmarket centers 40 referred to as “cooperative” market centers maydisclose both the displayed quantities and the reserved quantities oftrading orders 12 to trading platform 50. Other market centers 40referred to as “non-cooperative” market centers may disclose only thedisplayed quantities of trading orders 12 to trading platform 50.

Trading platform 50 is a trading architecture that facilitates therouting, matching, and otherwise processing of trading orders 12.Trading platform 50 may comprise a management center or a headquarteringoffice for any person, business, or entity that seeks to route,allocate, match, process, or fill trading orders 12. Accordingly,trading platform 50 may include any suitable combination of hardware,software, personnel, devices, components, elements, or objects that maybe utilized or implemented to achieve the operations and functions of anadministrative body or a supervising entity that manages or administersa trading environment. In certain embodiments, trading platform 50comprises client interface 52, market interface 54, processor 56, andmemory module 60.

Client interface 52 of trading platform 50 is communicatively coupled tonetwork 30 and supports communications between clients 20 and thevarious components of trading platform 50. According to certainembodiments, client interface 52 comprises a transaction server thatreceives trading orders 12 communicated by clients 20 via network 30.

Market interface 54 is communicatively coupled to market centers 40 andsupports communications between market centers 40 and the variouscomponents of trading platform 50. Market interface 54 may comprise atransaction server that receives trading orders 12 communicated bymarket centers 40. Market interface 54 may be operable to send to marketcenters 40 trading orders 12 received from clients 20 connected directlyto trading platform 50.

Client interface 52 and market interface 54 are communicatively coupledto processor 56. Processor 56 is operable to record trading orders 12 inmemory module 60 and route trading orders 12 to market centers 40.Processor 56 is further operable to execute logic 62 stored in memorymodule 60 to match buy orders 14 and sell orders 16 received by clientinterface 52 and market interface 54. In addition, processor 56 isoperable to incrementally fill a particular trading order 12 by usingthe reserved quantity of that trading order 12 to replenish thedisplayed quantity of that trading order 12. In some embodiments,processor 56 may cause the reserved quantity of trading order 12 todecay over time. Processor 56 may comprise any suitable combination ofhardware and software implemented in one or more modules to provide thedescribed function or operation.

For example, processor 56 may cause the reserved quantity of tradingorder 12 to decay over time in accordance with decay rule 66. Decay rule66 may be stored in memory module 60. The trading order 12 may includedecay rule 66. Decay rule 66 may be embedded within trading order 12.Decay rule 66 may be part of a data signal that includes trading order12. Processor 56 may retrieve decay rule 66 from the trading order 12and store decay rule 66 in memory module 60. Processor 56 may processtrading order 12 and decay rule 66 (e.g., included in trading order 12)without storing decay rule 66 in memory module 60.

Memory module 60 comprises any suitable arrangement of random accessmemory (RAM), read only memory (ROM), magnetic computer disk, CD-ROM, orother magnetic or optical storage media, or any other volatile ornon-volatile memory devices that store one or more files, lists, tables,or other arrangements of information such as trading orders 12. AlthoughFIG. 1 illustrates memory module 60 as internal to trading platform 50,it should be understood that memory module 60 may be internal orexternal to components of trading system 10, depending on particularimplementations. Also, memory module 60 illustrated in FIG. 1 may beseparate or integral to other memory devices to achieve any suitablearrangement of memory devices for use in trading system 10.

According to certain embodiments, memory module 60 stores logic 62 andtrader profiles 64. Logic 62 generally comprises software instructionsfor routing, matching, processing, or filling trading orders 12.Processor 56 is operable to execute logic 62 in memory module 60 tomatch buy orders 14 and sell orders 16 and to determine the priority oftraders 70 associated with those buy orders 14 and sell orders 16.

Memory module 60 may store a respective trader profile 64 for eachtrader 70 in trading system 10. Trader profile 64 for a particulartrader 70 may comprise the name, account information, tradingpreferences, trade history, and/or other suitable information associatedwith the particular trader 70. In some embodiments, trader profile 64comprises one or more decay rules 66.

The trading order 12 may include decay rule 66. Decay rule 66 may beembedded within trading order 12. Decay rule 66 may be part of a datasignal that includes trading order 12. A trading order 12 may includeone or more decay rules 66.

Processor 56 may execute decay rule 66 (e.g., stored in memory module 60and/or specified by trading order 12 as described above) to determinethe rate and/or frequency at which to reduce the reserved quantity oftrading order 12. Decay rule 66 may specify an amount by which thereserved quantity of trading order 12 should decay over time. Forexample, decay rule 66 may direct processor to reduce the reservedquantity of trading order 12 by one thousand units per minute. Byreducing the reserved quantity of trading order 12 over time, processormay reduce the risks associated with having a stale trading order 12 ina volatile market. In some embodiments, a particular decay rule 66 maybe associated with a decay interval 68 and a decay rate 72 (describedbelow with respect to FIG. 2).

It should be understood that the internal structure of trading platform50 and the interfaces, processors, and memory devices associatedtherewith is malleable and can be readily changed, modified, rearranged,or reconfigured in order to achieve the intended operations of tradingplatform 50.

In operation, trading platform 50 is operable to receive trading order12 from client 20. Trading order 12 may be for a particular quantity ofa particular trading product (e.g., equities, commodities, futures,currencies, bonds, and so forth). In some embodiments, trading order 12designates a portion of the particular quantity as a displayed quantity.Trading order 12 may designate another portion of the particularquantity of trading order 12 as the reserved quantity. Trading platform50 may disclose the displayed quantity of trading order 12 to marketcenter 40. In some embodiments, trading platform 50 prevents thedisclosure of the reserved quantity of trading order 12 to market center40.

Upon receiving trading order 12, processor 56 may identify decay rule 66stored in memory module 60. Decay rule 66 may instruct processor 56 toreduce the reserved quantity of trading order 12 over time. Reducing thereserved quantity of trading order 12 may comprise deleting a portion oftrading order 12 from one or more order books 74 in memory module 60. Insome embodiments, the reduction of the reserved quantity of tradingorder 12 is based at least in part on decay rate 72 associated withdecay rule 66.

In addition to specifying displayed and reserved quantities of aparticular trading product, trading order 12 (or, e.g., a data signalthat includes or accompanies trading order 12) may specify a decay rule66. Thus, the trading order 12 may include decay rule 66. Decay rule 66may be embedded within trading order 12. Trading order 12 may storedecay rule 66. Decay rule 66 may be part of a data signal that includestrading order 12. A trading order 12 may include one or more decay rules66.

The decay rule 66 (e.g., included in trading order 12) may specify,e.g., a decay interval, a decay rate, and/or a decay quantity. Thetrading order 12 may specify, e.g., a decay interval, decay rate, and/ora decay quantity in addition to a decay rule 66.

Although decay rule(s) 66, decay interval(s) 68, and decay rate(s) 72are shown in FIG. 1 as being stored in the trading platform 50 in memorymodule 60, any of decay rule(s) 66, decay interval(s) 68, and decayrate(s) 72, etc., may be included in trading order 12. Any subsequentdescription of, e.g., processor 56 retrieving a decay rule 66 frommemory module 60 is merely an example, and processor 56 may instead, orin addition, retrieve a decay rule 66 from trading order 12.

Thus, upon receiving trading order 12, processor 56 may identify decayrule 66 stored in memory module 60. Upon receiving trading order 12,processor 56 may retrieve, e.g., decay rule 66 from trading order 12.Processor 56 may store, e.g., decay rule 66 in memory module 60.Processor 56 may update decay rule 66 in memory module 60 based on adecay rule stored in trading order 12. Upon receiving trading order 12,processor 56 may process trading order 12 and, e.g., any associateddecay rule 66 without storing, e.g., the decay rule 66 in memory module60.

In some embodiments, upon receiving trading order 12, processor 56 mayretrieve a decay rule 66 from memory module 60 and may retrieve specificvalues or inputs, e.g., any of a decay interval, a decay rate, a decayquantity, etc., from trading order 12. That is, trading order 12 mayinclude a particular value of decay interval 68, decay rate 72, and/or adecay quantity. Processor 56 may receive the trading order 12 and mayretrieve one or more specific values (e.g., decay rate 72) from tradingorder 12, and execute a decay rule 66 stored in memory module 60 usingthese values.

FIG. 2 is a table 200 that sets forth an example illustrating the decayof trading order 12, according to certain embodiments. In this example,one or more decay rules 66 (e.g., stored in memory module 60 and/orspecified by trading order 12 as described above) cause the reservedquantity of trading order 12 to decay over time. As each successiveinterval of time expires, processor 56 may reduce the reserved quantityof trading order 12 by a configurable increment. The time intervals atwhich the reserved quantity decays may be referred to as decay intervals68. The rate at which the reserved quantity decays may be referred to asdecay rate 72. For example, decay rule 66 may specify that, at theexpiration of each successive minute after trading platform 50 receivestrading order 12, processor 56 reduces reserved quantity of tradingorder 12 by five million units. In this example, decay interval 68 isone minute and decay rate 72 is five million units/minute. Although theforegoing example illustrates decay interval 68 of one minute, it shouldbe understood that decay interval 68 may be ten seconds, two minutes,ten minutes, and/or any suitable interval of time. Although theforegoing example illustrates decay rate 72 of five millionunits/minute, it should be understood that decay rate 72 may be onehundred units/second, one million units/minute, and/or any suitablerate.

In some embodiments, once processor 56 uses counterorder 12 b to fillthe displayed quantity of order 12 a, processor 56 may replenish thedisplayed quantity of order 12 a. In particular, processor 56 may beconfigured to use a portion of the reserved quantity of order 12 a toreplenish the displayed quantity of order 12 a. In some embodiments, thefilling and replenishing of the displayed quantity of order 12 a occursindependently of the decay of the reserved quantity of order 12 a.

The example order 12 a in table 200 illustrates certain embodiments. Inthis example, trading platform 50 comprises decay rule 66 (and/or, e.g.,trading order 12 specifies decay rule 66) to reduce the reservedquantity of trading order 12 by twenty million units per minute. In thisexample, at 10:26:02 a.m., trading platform 50 receives Bid A fromTrader A. Bid A is for one hundred million units of Security X at aprice of two dollars per unit. The trading product and price associatedwith Bid A is illustrated in columns 202 and 204, respectively. Bid Ahas a displayed quantity of ten million units and a reserved quantity ofninety million units. The displayed quantity and reserved quantity ofBid A is illustrated in columns 206 and 208, respectively.

Upon receiving Bid A, processor 56 discloses the displayed quantity(i.e., ten million units) of Bid A to market centers 40. At 10:26:34a.m., trading platform 50 receives Offer B, a matching counterorder 12b. Offer B is for ten million units of Security X at two dollars perunit. Upon receiving Offer B, processor 56 uses the ten million unitsfrom Offer B to fill the displayed quantity of Bid A. Processor 56 thenuses ten million units from the reserved quantity of Bid A to replenishthe displayed quantity of Bid A. Thus, the reserved quantity of Bid Abecomes eighty million units.

In this example, trading platform 50 does not receive any other matchingcounterorders 12 b prior to 10:27:02 a.m.—one minute after tradingplatform 50 received Bid A. According to decay rule 66, at 10:27:02a.m., processor 56 reduces reserved quantity of Bid A from eightymillion units to sixty million units. With the expiration of eachsuccessive minute, processor 56 continues to reduce reserved quantity ofBid A according to decay rule 66. By decaying the reserved quantity ofBid A over time, processor 56 may reduce certain risks associated withmarket volatility. In particular, by reducing the reserved quantity ofBid A over time, processor 56 may reduce the risk of Trader A havingexposure for a stale trading order 12 with a price that is no longerfavorable for Trader A.

In some embodiments, trading platform 50 may comprise different decayrules 66 for different traders 70. In particular, memory module 60 maystore a respective trader profile 64 for each trader 70 in tradingsystem 10. Trader profile 64 for a particular trader 70 may comprise oneor more decay rules 66 that are configurable by that trader 70. In someembodiments, a particular trader profile 64 may comprise a first decayrule 66 for a first trading product, a second decay rule 66 for a secondtrading product, and so forth. Thus, a particular trader 70 may causethe reserved quantity of trading order 12 for a first trading product todecay at a different rate than the reserved quantity of trading order 12for a second trading product. In some embodiments, upon receivingtrading order 12, processor 56 identifies the particular trader 70 thatsubmitted trading order 12. Processor 56 may then identify in memorymodule 60 trader profile 64 associated with the particular trader 70.Processor 56 may then retrieve the appropriate decay rule 66 from theidentified trader profile 64. Thus, processor 56 may apply differentdecay rules 66 for different traders 70. Processor 56 may update a decayrule 66 included in a trader profile 64 based on a decay rule 66 from areceived trading order 12.

Although decay rule(s) 66, decay interval(s) 68, and decay rate(s) 72are shown in FIG. 1 as being stored in the trading platform 50 in memorymodule 60, any of decay rule(s) 66, decay interval(s) 68, and decayrate(s) 72, etc., may be included in trading order 12. Trading order 12for a particular trading product may include, e.g., one or more decayrules 66 (and/or decay intervals, decay rates, decay quantities, etc.)associated with the particular trading product (or, e.g., any tradingproducts that are related to the particular trading product). Tradingorder 12 originating from a particular trader may include, e.g., one ormore decay rules 66 (and/or decay intervals, decay rates, decayquantities, etc.) associated with the particular trader (e.g., based onpreferences of the particular trader).

In some embodiments, decay rule 66 may specify an initial decay interval68 that is longer or shorter than successive decay intervals 68. Forexample, a particular decay rule 66 may specify that, five minutes aftertrading platform 50 received trading order 12, processor 56 beginsdecaying the reserved quantity of trading order 12. After the initialfive minute interval, the particular decay rule 66 may specify thatprocessor 56 continue to decay the reserved quantity after eachsuccessive minute.

Decay rule 66 may comprise any suitable formula, table, algorithm,and/or instructions for reducing the reserved quantity of trading order12. In some embodiments, decay rule 66 may comprise a formula for avariable decay rate 72. For example, decay rule 66 may be a formula foran exponentially increasing decay rate 72.

FIG. 3 is a table 300 that sets forth an example illustrating variablerate decay of trading order 12, according to certain embodiments. Inthis example, decay rule 66 (e.g., stored in memory module 60 and/orspecified by trading order 12 as described above) instructs processor 56to decay the reserved quantity of trading order 12 at a rate of “10 T”where “T” is the number of minutes since trading platform 50 receivedtrading order 12. At 11:42:12 a.m., trading platform 50 receives Bid Afor one hundred units of Security Y. Bid A comprises a displayedquantity of ten units and a reserved quantity of ninety units. Thetrading product, displayed quantity, and reserved quantity associatedwith Bid A are illustrated in columns 302, 304, and 306, respectively.

In this example, processor 56 reduces the reserved quantity of Bid Aaccording to decay rule 66. In particular, at 11:43:12 a.m., processor56 reduces the reserved quantity of Bid A by ten units (i.e., 10×1). At11:44:12 a.m., processor 56 further reduces the reserved quantity of BidA by twenty units (i.e., 10×2). With each successive minute, processor56 reduces the reserved quantity of Bid A by an increasing amountaccording to decay rule 66. The decay of the reserved quantity maycontinue until the reserved quantity is eliminated. Thus, decay rule 66may specify a variable decay rate 72.

Although the foregoing example illustrates decay rate 72 associated witha particular formula, it should be understood that decay rule 66 maycomprise any suitable formula, table, algorithm, and/or instructions forreducing the reserved quantity of trading order 12 over time.

For example, in some embodiments, decay rule 66 is configured to causethe reserved quantity of trading order 12 to decay over time in responseto one or more conditions.

Trading order 12 may specify decay rule 66 which may in turn specify theone or more conditions as well as, e.g., a decay interval, a decay rate,and/or a decay quantity, etc.

For example, for a trading order 12 for a particular trading product, acondition may relate to a market price of the particular tradingproduct. For example, if the market price goes below (or, e.g., above) acertain value, then the reserved quantity (of the particular tradingproduct) specified by trading order 12 should decay at, e.g., aparticular decay rate 72 embedded in the trading order 12.

The condition may relate to market activity external to the particulartrading product of a trading order 12. For example, the condition mightinvolve a market index such as the Dow Jones Industrial Average. Forexample, if the Dow Jones Industrial Average goes below (or, e.g.,above) a certain value, then the reserved quantity of trading order 12should decay, e.g., according to a particular decay interval 68 anddecay quantity specified by the trading order 12.

The condition may relate to market activity external to, but moredirectly related to the particular trading product of a trading order12. For example, if the trading order concerns a bid/offer for theparticular trading product in a cash market, the condition might involvea bid/offer for a derivative financial instrument based on theparticular trading product in a futures market. For example, if thequantity available of the derivative financial instrument at aparticular price of interest goes below (or, e.g., above) a certainvalue, then reserved quantity of trading order 12 should decay, e.g.,according to the decay rule 66 specified by the trading order 12.

The condition may relate to one or more products identified by, e.g., aprocess implemented by trading platform 50 (or by, e.g., a tradersubmitting the trading order 12) as being related (e.g., substantiallyequivalent) to a particular trading product of a trading order 12.

For example, as described in more detail in U.S. patent application Ser.Nos. 11/399,019 and 11/399,112, both filed on Apr. 5, 2006, and each ofwhich is hereby incorporated by reference herein in its entirety,trading platform 50 may be operable to identify relationships betweentrading products. Trading products may be related in a number of ways.For example, the historical performance of a ten-year note issued byentity X may be correlated to that of a five-year note issued by entityX. Although they are different trading products, the ten-year note andthe five-year note share the same trading entity and are correlated intheir performance trends. Thus, a trader who is interested in tradingten-year notes issued by entity X may also be interested in tradingfive-year notes issued by entity X.

The trading platform 50 may be operable to use current market data todetermine a quantity of a particular trading product that may beequivalent to a quantity of a related trading product. For example,trading platform 50 may determine how may five-year notes are equivalentto a number of ten-year notes. Such a calculation may be based on anysuitable number and combination of factors such as, for example, thecoupons, frequencies, face values, prices, and maturity dates offive-year and ten-year notes.

The trading platform 50 may be operable to determine the liquidityassociated with particular trading products. The liquidity associatedwith a trading product refers to the volume of trading product availablefor trading in market centers 40. At any given time, the tradingplatform 50 may determine the available volume of a particular tradingproduct in market centers 40.

Using at least market data from, e.g., the market centers 40, thetrading platform 50 may generate a composite value. The composite valuemay be single value that encompasses the relationships among and theliquidity of multiple trading products in multiple market centers 40. Inparticular, composite value may represent a quantity, size, or any othermeasurement of one or more related products that are available for tradein various market centers 40 at any given time. Composite value may bebased on any suitable mathematical calculations and/or models fordetermining relationships among trading products. As an example,composite value may be configured to represent a quantity of “10-yearequivalent” fixed income securities available for trade in marketcenters 40. The quantity of 10-year equivalent securities may encompassthe total number of available 10-year notes as well as a weightedquantity of 2-year notes, 3-year notes, 5-year notes, and/or any othersuitable number and combination of related trading products. Theweighted quantity of related trading products (e.g., 2-year notes,3-year notes, 5-year notes, etc.) may be incorporated into compositevalue because that weighted quantity may be considered substantiallyequivalent (e.g., in performance, yield, price sensitivity to movementsin a yield curve, and/or any other suitable number and combination ofcharacteristics) to 10-year notes.

Conditions in decay rules 66 may involve, e.g., relationships betweentrading products, quantities between related trading products based on adetermination that a quantity of a particular trading product may beequivalent to a quantity of a related trading product, liquidity ofrelated trading products in market centers 40, and composite value(s)determined for one or more related trading products.

For example, a condition in a decay rule 66 might involve a tradingproduct that has been determined to be related to a particular tradingproduct of trading order 12. For example, if the quantity available ofthe related trading product at a particular price of interest goes below(or, e.g., above) a certain value, then reserved quantity of tradingorder 12 should decay, e.g., according to the decay rule 66 specified bythe trading order 12.

The condition may relate to activity external to the particular tradingproduct of a trading order 12. For example, the condition might involvea result of an event seemingly unrelated to the trading product of atrading order 12, such as a result of a sporting event or an election.As an extreme example for illustrative purposes, the condition mightinvolve a time during the trading day. For example, if the time of theday is, e.g., after 3 P.M., and the market is going to close for the dayin, say, an hour, a particular decay rule 66 may be operative or, thetime may trigger, e.g., a higher decay rate 72 than might be used atother times of the day.

FIG. 4 illustrates a flowchart for managing trading orders 12, accordingto certain embodiments. The method begins at step 402 where tradingplatform 50 receives order 12 a from client 20. Order 12 a may specify,e.g., decay rule 66 as described above. Decay rule 66 may specify decayinterval 68 and/or decay rule 72. Order 12 a may be for a particularquantity of a trading product. A portion of the particular quantity oforder 12 a may be designated as a displayed quantity. The remainingportion of the particular quantity of order 12 a may be designated asthe reserved quantity. At step 404, trading platform 50 discloses thedisplayed quantity of order 12 a to market centers 40. Disclosing thedisplayed quantity of order 12 a may comprise transmitting dataregarding the displayed quantity of order 12 a to market centers 40.

At step 406, processor 56 determines whether trading platform 50 hasreceived counterorder 12 b that matches order 12 a. In some embodiments,the determination of whether counterorder 12 b matches order 12 a isbased at least in part on whether counterorder 12 b and order 12 a arefor the same product, the same price, and/or or crossing prices. Ifprocessor 56 determines at step 406 that trading platform 50 has notreceived counterorder 12 b that matches order 12 a, then the methodproceeds to step 414. However, if processor 56 determines at step 406that trading platform 50 has received counterorder 12 b that matchesorder 12 a, then at step 408 processor 56 uses the counterorder 12 b tofill the displayed quantity of order 12 a. At step 410, processor 56determines whether the reserved quantity of order 12 a is greater thanzero. If processor 56 determines at step 410 that the reserved quantityof order 12 a is not greater than zero, then the method ends. However,if processor 56 determines at step 410 that the reserved quantity oforder 12 a is greater than zero, then at step 412 processor 56 uses aportion of the reserved quantity of order 12 a to replenish thedisplayed quantity of order 12 a. The method then proceeds to step 414.

At step 414, processor 56 determines whether decay interval 68associated with decay rule 66 (e.g., stored in memory module 60 and/orspecified by trading order 12 as described above) has expired. Ifprocessor 56 determines at step 414 that decay interval 68 has notexpired, then the method returns to step 406. However, if processor 56determines at step 414 that decay interval 68 has expired, then at step416 processor 56 determines whether the reserved quantity of order 12 ais greater than zero. If processor 56 determines at step 416 that thereserved quantity is not greater than zero, then the method returns tostep 406. However, if processor 56 determines at step 416 that thereserved quantity is greater than zero, then at step 418 processor 56reduces the reserved quantity of order 12 a by a configurable amountaccording to decay rule 66. Decay rule 66 may comprise any suitableformula, table, algorithm, and/or instructions for reducing the reservedquantity of order 12 a over time. Decay rule 66 may specify any suitablelength of decay interval 68 and/or may specify any suitable decay rate72. After processor 56 reduces the reserved quantity of order 12 a atstep 418, the method returns to step 406. The method ends when, at step410, processor 56 determines that the reserved quantity of order 12 a isnot greater than zero. In some embodiments, the method may also end whenorder 12 a expires and/or when trading platform 50 receives a cancelorder associated with order 12 a.

Further Embodiments

The following should be interpreted as further embodiments and not asclaims.

A1. A system, comprising:

-   -   a memory operable to store a trading order for a particular        quantity of a trading product, wherein:        -   a first portion of the particular quantity is a displayed            quantity; and        -   a second portion of the particular quantity is a reserved            quantity;    -   a processor communicatively coupled to the memory and operable        to:        -   disclose the displayed quantity to one or more market            centers;        -   identify a decay rate associated with the trading order; and        -   cause the reserved quantity to decay based at least in part            on the identified decay rate.

A2. The system of A1, wherein:

-   -   the trading order is received at a first time;    -   the decay rate is associated with a decay quantity and a time        interval; and    -   causing the reserved quantity to decay based at least in part on        the identified decay rate comprises:        -   in response to expiration of the time interval after the            first time, subtracting the decay quantity from the reserved            quantity; and        -   in response to expiration of each successive time interval,            subtracting the decay quantity from the reserved quantity            such that the reserved quantity decays until the reserved            quantity is eliminated.

A3. The system of A1, wherein:

-   -   the decay rate is associated with a time interval; and    -   the decay rate is a variable rate such that, upon expiration of        each successive time interval, the reserved quantity diminishes        at an increasing rate.

A4. The system of A1, wherein:

-   -   the decay rate is associated with a time interval; and    -   the decay rate is a variable rate such that, upon expiration of        each successive time interval, the reserved quantity diminishes        at a decreasing rate.

A5. The system of A1, wherein the processor is further operable to:

-   -   receive a counterorder for the trading product;    -   fill the displayed quantity of the trading order with a portion        of the counterorder; and    -   replenish the displayed quantity of the trading order with a        portion of the reserved quantity of the trading order.

A6. The system of A5, wherein the displayed quantity of the tradingorder is replenished independently of the decay of the reservedquantity.

A7. The system of A1, wherein:

-   -   the trading order is from a first trader;    -   the processor is further operable to receive a second trading        order for the trading product;    -   the second trading order comprises a second displayed quantity        and a second reserved quantity;    -   the second trading order is from a second trader; and    -   the processor is further operable to:        -   identify a second decay rate associated with the second            trader; and        -   cause the second reserved quantity to decay based at least            in part on the second decay rate.

A8. The system of A1, wherein:

-   -   the decay rate is a first decay rate and the trading product is        a first trading product; and    -   the memory is further operable to storing a plurality of decay        rates, wherein each decay rate is associated with a respective        trading product.

A9. The system of A1, wherein:

-   -   the processor is further operable to record the displayed        quantity and the reserved quantity in an order book; and    -   causing the reserved quantity to decay based at least in part on        the identified decay rate comprises:    -   in response to expiration of a first time interval, deleting a        first portion of the reserved quantity from the order book; and    -   in response to expiration of a second time interval, deleting a        second portion of the reserved quantity from the order book.

B1. A method, comprising:

-   -   receiving a trading order for a particular quantity of a trading        product, wherein:        -   a first portion of the particular quantity is a displayed            quantity; and        -   a second portion of the particular quantity is a reserved            quantity;    -   disclosing the displayed quantity to one or more market centers;    -   identifying a decay rate associated with the trading order; and    -   causing the reserved quantity to decay based at least in part on        the identified decay rate.

B2. The method of B1, wherein:

-   -   the trading order is received at a first time;    -   the decay rate is associated with a decay quantity and a time        interval; and    -   causing the reserved quantity to decay based at least in part on        the identified decay rate comprises:        -   in response to expiration of the time interval after the            first time, subtracting the decay quantity from the reserved            quantity; and        -   in response to expiration of each successive time interval,            subtracting the decay quantity from the reserved quantity            such that the reserved quantity decays until the reserved            quantity is eliminated.

B3. The method of B1, wherein:

-   -   the decay rate is associated with a time interval; and    -   the decay rate is a variable rate such that, upon expiration of        each successive time interval, the reserved quantity diminishes        at an increasing rate.

B4. The method of B1, wherein:

-   -   the decay rate is associated with a time interval; and    -   the decay rate is a variable rate such that, upon expiration of        each successive time interval, the reserved quantity diminishes        at a decreasing rate.

B5. The method of B1, further comprising:

-   -   receiving a counterorder for the trading product;    -   filling the displayed quantity of the trading order with a        portion of the counterorder; and    -   replenishing the displayed quantity of the trading order with a        portion of the reserved quantity of the trading order.

B6. The method of B5, wherein the displayed quantity of the tradingorder is replenished independently of the decay of the reservedquantity.

B7. The method of B1, wherein:

-   -   the trading order is from a first trader;    -   and further comprising:    -   receiving a second trading order for the trading product,        wherein:        -   the second trading order comprises a second displayed            quantity and a second reserved quantity; and        -   the second trading order is from a second trader;    -   identifying a second decay rate associated with the second        trader; and    -   causing the second reserved quantity to decay based at least in        part on the second decay rate.

B8. The method of B1, wherein:

-   -   the decay rate is a first decay rate and the trading product is        a first trading product;    -   and further comprising:    -   storing a plurality of decay rates, wherein each decay rate is        associated with a respective trading product.

B9. The method of B1, further comprising:

-   -   recording the displayed quantity and the reserved quantity in an        order book;    -   wherein causing the reserved quantity to decay based at least in        part on the identified decay rate comprises:        -   in response to expiration of a first time interval, deleting            a first portion of the reserved quantity from the order            book; and        -   in response to expiration of a second time interval,            deleting a second portion of the reserved quantity from the            order book.

C1. Logic encoded in computer-readable media and operable when executedby a processor to:

-   -   receive a trading order for a particular quantity of a trading        product, wherein:        -   a first portion of the particular quantity is a displayed            quantity; and        -   a second portion of the particular quantity is a reserved            quantity;    -   disclose the displayed quantity to one or more market centers;    -   identify a decay rate associated with the trading order; and    -   cause the reserved quantity to decay based at least in part on        the identified decay rate.

C2. The logic of C1, wherein:

-   -   the trading order is received at a first time;    -   the decay rate is associated with a decay quantity and a time        interval; and    -   causing the reserved quantity to decay based at least in part on        the identified decay rate comprises:        -   in response to expiration of the time interval after the            first time, subtracting the decay quantity from the reserved            quantity; and        -   in response to expiration of each successive time interval,            subtracting the decay quantity from the reserved quantity            such that the reserved quantity decays until the reserved            quantity is eliminated.

D1. An apparatus, comprising:

-   -   a processor; and    -   a memory, in which the memory is communicatively coupled to the        processor, and in which the memory stores software instructions        that, when executed by the processor, cause the processor to:        -   receive, from a trader at a first time, a trading order for            a particular quantity of a trading product, in which a first            portion of the particular quantity is a displayed quantity,            and a second portion of the particular quantity is a            reserved quantity, and in which the trading order specifies            a decay rule;        -   identify the decay rule from the trading order, in which the            decay rule is associated with at least one of the trader and            the trading product, and in which the decay rule specifies            at least a variable decay rate and a time interval;        -   disclose the displayed quantity of the trading order to one            or more market centers;        -   receive a counterorder for another particular quantity of            the trading product;        -   determine that the counterorder matches the trading order;        -   fill the displayed quantity of the trading order with at            least a portion of the another particular quantity of the            counterorder;        -   determine that the reserved quantity of the trading order is            greater than zero;        -   replenish the displayed quantity of the trading order with a            portion of the reserved quantity of the trading order, in            which a remaining portion of the reserved quantity is left            over after replenishing the displayed quantity;        -   determine that the time interval after the first time has            expired;        -   after determining that the time interval after the first            time has expired, determine that the remaining portion of            the reserved quantity of the trading order is greater than            zero;        -   reduce the remaining portion of the reserved quantity in            accordance with the decay rule, in which any replenishing of            the displayed quantity of the trading order occurs            independently of reducing the remaining portion of the            reserved quantity in accordance with the decay rule, and in            which reducing the remaining portion of the reserved            quantity in accordance with the decay rule comprises:            -   after determining that the time interval after the first                time has expired, reducing the remaining portion of the                reserved quantity by a first quantity; and        -   increase the variable decay rate; and        -   after an expiration of a successive time interval after the            time interval, reduce the remaining portion of the reserved            quantity by a second quantity, in which the second quantity            is larger than the first quantity.

D2. The apparatus of D1, in which the software instructions, whenexecuted by the processor, further cause the processor to:

-   -   receive, from a second trader at a second time, a second trading        order for still another particular quantity of the trading        product, in which the still another particular quantity of the        trading product comprises a second displayed quantity and a        second reserved quantity, and in which the second trading order        specifies a second decay rule; and    -   identify the second decay rule from the second trading order, in        which the second decay rule is associated with at least the        second trader and the trading product, and in which the second        decay rule specifies at least a decay quantity.

D3. The apparatus of D2, in which the second decay rule furtherspecifies at least a second time interval; and in which the softwareinstructions, when executed by the processor, further cause theprocessor to:

-   -   determine that the second time interval after the second time        has expired;    -   in response to determining that the second time interval after        the second time has expired, subtract the decay quantity from        the second reserved quantity; and    -   for each second successive time interval until the second        reserved quantity is zero, in response to an expiration of the        second successive time interval, subtract the decay quantity        from the second reserved quantity.

D4. The apparatus of D2, in which the software instructions, whenexecuted by the processor, further cause the processor to:

-   -   cause the second reserved quantity of the second trading order        to decay based at least in part on the decay quantity.

D5. The apparatus of D1, in which the software instructions, whenexecuted by the processor, further cause the processor to:

-   -   upon receiving the trading order from the trader, identify the        trader;    -   identify a trader profile associated with the trader; and    -   update another decay rule stored in the trader profile based at        least in part on the decay rule from the trading order, in which        the decay rule is associated with at least the trader.

D6. The apparatus of D1, in which the software instructions, whenexecuted by the processor, further cause the processor to:

-   -   receive, from a second trader, a second trading order for still        another particular quantity of the trading product, in which the        still another particular quantity of the trading product        comprises a second displayed quantity and a second reserved        quantity, and in which the second trading order specifies a        second decay rule; and    -   identify the second decay rule from the second trading order, in        which the second decay rule is associated with at least the        second trader and the trading product, and in which the second        decay rule specifies at least a second decay rate; and    -   cause the second reserved quantity of the second trading order        to decay based at least in part on the second decay rate.

D7. The apparatus of D1, in which the variable decay rate is a firstdecay rate and the trading product is a first trading product of aplurality of trading products; and

in which the software instructions, when executed by the processor,further cause the processor to:

-   -   store a plurality of decay rates in the memory, in which each        decay rate of the plurality of decay rates is associated with a        respective trading product of the plurality of trading products.

D8. The apparatus of D1, in which the software instructions, whenexecuted by the processor, further cause the processor to:

-   -   record at least the reserved quantity of the trading order in an        order book; and        in which reducing the remaining portion of the reserved quantity        by the first quantity comprises:    -   deleting the first quantity from the order book; and in which        reducing the remaining portion of the reserved quantity by the        second quantity comprises:    -   deleting the second quantity from the order book.

E1. A method, comprising:

-   -   receiving, from a trader at a first time, by a processor of a        computer, a trading order for a particular quantity of a trading        product, in which a first portion of the particular quantity is        a displayed quantity, and a second portion of the particular        quantity is a reserved quantity, and in which the trading order        specifies a decay rule;    -   identifying, by the processor, the decay rule from the trading        order, in which the decay rule is associated with at least one        of the trader and the trading product, and in which the decay        rule specifies at least a variable decay rate and a time        interval;    -   disclosing, by the processor, the displayed quantity of the        trading order to one or more market centers;    -   receiving, by the processor, a counterorder for another        particular quantity of the trading product;    -   determining, by the processor, that the counterorder matches the        trading order;    -   filling, by the processor, the displayed quantity of the trading        order with at least a portion of the another particular quantity        of the counterorder;    -   determining, by the processor, that the reserved quantity of the        trading order is greater than zero;    -   replenishing, by the processor, the displayed quantity of the        trading order with a portion of the reserved quantity of the        trading order, in which a remaining portion of the reserved        quantity is left over after replenishing the displayed quantity;    -   determining, by the processor, that the time interval after the        first time has expired;    -   after determining that the time interval after the first time        has expired, determining, by the processor, that the remaining        portion of the reserved quantity of the trading order is greater        than zero;    -   reducing, by the processor, the remaining portion of the        reserved quantity in accordance with the decay rule, in which        any replenishing of the displayed quantity of the trading order        occurs independently of reducing the remaining portion of the        reserved quantity in accordance with the decay rule, and in        which reducing the remaining portion of the reserved quantity in        accordance with the decay rule comprises:        -   after determining that the time interval after the first            time has expired, reducing, by the processor, the remaining            portion of the reserved quantity by a first quantity; and    -   increasing, by the processor, the variable decay rate; and    -   after an expiration of a successive time interval after the time        interval, reducing, by the processor, the remaining portion of        the reserved quantity by a second quantity, in which the second        quantity is larger than the first quantity.

E2. The method of E1, further comprising:

-   -   receive, by the processor, from a second trader at a second        time, a second trading order for still another particular        quantity of the trading product, in which the still another        particular quantity of the trading product comprises a second        displayed quantity and a second reserved quantity, and in which        the second trading order specifies a second decay rule; and    -   identifying, by the processor, the second decay rule from the        second trading order, in which the second decay rule is        associated with at least the second trader and the trading        product, and in which the second decay rule specifies at least a        decay quantity.

E3. The method of E2, in which the second decay rule further specifiesat least a second time interval; and

in which the method further comprises:

-   -   determining, by the processor, that the second time interval        after the second time has expired;    -   in response to determining that the second time interval after        the second time has expired, subtracting, by the processor, the        decay quantity from the second reserved quantity; and    -   for each second successive time interval until the second        reserved quantity is zero, in response to an expiration of the        second successive time interval, subtracting, by the processor.        the decay quantity from the second reserved quantity.

E4. The method of E2, further comprising:

-   -   causing, by the processor, the second reserved quantity of the        second trading order to decay based at least in part on the        decay quantity.

E5. The method of E1, further comprising:

-   -   upon receiving the trading order from the trader, identifying,        by the processor, the trader;    -   identifying, by the processor, a trader profile associated with        the trader; and    -   updating, by the processor, another decay rule stored in the        trader profile based at least in part on the decay rule from the        trading order, in which the decay rule is associated with at        least the trader.

E6. The method of E1, further comprising:

-   -   receiving, by the processor, from a second trader, a second        trading order for still another particular quantity of the        trading product, in which the still another particular quantity        of the trading product comprises a second displayed quantity and        a second reserved quantity, and in which the second trading        order specifies a second decay rule;    -   identifying, by the processor, the second decay rule from the        second trading order, in which the second decay rule is        associated with at least the second trader and the trading        product, and in which the second decay rule specifies at least a        second decay rate; and    -   causing, by the processor, the second reserved quantity of the        trading order to decay based at least in part on the second        decay rate.

E7. The method of E1, in which the variable decay rate is a first decayrate and the trading product is a first trading product of a pluralityof trading products; and

in which the method further comprises:

-   -   storing, by the processor, a plurality of decay rates, in which        each decay rate of the plurality of decay rates is associated        with a respective trading product of the plurality of trading        products.

E8. The method of E1, further comprising:

-   -   recording, by the processor, at least the reserved quantity of        the trading order in an order book; and        in which reducing the remaining portion of the reserved quantity        by the first quantity comprises:    -   deleting, by the processor, the first quantity from the order        book; and    -   deleting, by the processor, the second quantity from the order        book.

F1. A computer-readable medium, the computer-readable medium being atangible medium, the computer-readable medium storing softwareinstructions that, when executed by a processor, cause the processor to:

-   -   receive, from a trader at a first time, a trading order for a        particular quantity of a trading product, in which a first        portion of the particular quantity is a displayed quantity, and        a second portion of the particular quantity is a reserved        quantity, and in which the trading order specifies a decay rule;    -   identify the decay rule from the trading order, in which the        decay rule is associated with at least one of the trader and the        trading product, and in which the decay rule specifies at least        a variable decay rate and a time interval;    -   disclose the displayed quantity of the trading order to one or        more market centers;    -   receive a counterorder for another particular quantity of the        trading product;    -   determine that the counterorder matches the trading order;    -   fill the displayed quantity of the trading order with at least a        portion of the another particular quantity of the counterorder;    -   determine that the reserved quantity of the trading order is        greater than zero;    -   replenish the displayed quantity of the trading order with a        portion of the reserved quantity of the trading order, in which        a remaining portion of the reserved quantity is left over after        replenishing the displayed quantity;    -   determine that the time interval after the first time has        expired;    -   after determining that the time interval after the first time        has expired, determine that the remaining portion of the        reserved quantity of the trading order is greater than zero;    -   reduce the remaining portion of the reserved quantity in        accordance with the decay rule, in which any replenishing of the        displayed quantity of the trading order occurs independently of        reducing the remaining portion of the reserved quantity in        accordance with the decay rule, and in which reducing the        remaining portion of the reserved quantity in accordance with        the decay rule comprises:        -   after determining that the time interval after the first            time has expired, reducing the remaining portion of the            reserved quantity by a first quantity; and    -   increase the variable decay rate; and    -   after an expiration of a successive time interval after the time        interval, reduce the remaining portion of the reserved quantity        by a second quantity, in which the second quantity is larger        than the first quantity.

F2. The computer-readable medium of F1, in which the softwareinstructions, when executed by the processor, further cause theprocessor to:

-   -   receive, from a second trader at a second time, a second trading        order for still another particular quantity of the trading        product, in which the still another particular quantity of the        trading product comprises a second displayed quantity and a        second reserved quantity, and in which the second trading order        specifies a second decay rule; and    -   identify the second decay rule from the second trading order, in        which the second decay rule is associated with at least the        second trader and the trading product, and in which the second        decay rule specifies at least a decay quantity.

F3. The computer-readable medium of F2, in which the second decay rulefurther specifies at least a second time interval; and in which thesoftware instructions, when executed by the processor, further cause theprocessor to:

-   -   determine that the second time interval after the second time        has expired;    -   in response to determining that the second time interval after        the second time has expired, subtract the decay quantity from        the second reserved quantity; and    -   for each second successive time interval until the second        reserved quantity is zero, in response to an expiration of the        second successive time interval, subtract the decay quantity        from the second reserved quantity.

F4. The computer-readable medium of F2, in which the softwareinstructions, when executed by the processor, further cause theprocessor to:

-   -   cause the second reserved quantity of the second trading order        to decay based at least in part on the decay quantity.

F5. The computer-readable medium of F1, in which the softwareinstructions, when executed by the processor, further cause theprocessor to:

-   -   upon receiving the trading order from the trader, identify the        trader;    -   identify a trader profile associated with the trader; and    -   update another decay rule stored in the trader profile based at        least in part on the decay rule from the trading order, in which        the decay rule is associated with at least the trader.

F6. The computer-readable medium of F1, in which the softwareinstructions, when executed by the processor, further cause theprocessor to:

-   -   receive, from a second trader, a second trading order for still        another particular quantity of the trading product, in which the        still another particular quantity of the trading product        comprises a second displayed quantity and a second reserved        quantity, and in which the second trading order specifies a        second decay rule; and    -   identify the second decay rule from the second trading order, in        which the second decay rule is associated with at least the        second trader and the trading product, and in which the second        decay rule specifies at least a second decay rate; and    -   cause the second reserved quantity of the second trading order        to decay based at least in part on the second decay rate.

F7. The computer-readable medium of F1, in which the variable decay rateis a first decay rate and the trading product is a first trading productof a plurality of trading products; and

in which the software instructions, when executed by the processor,further cause the processor to:

-   -   store a plurality of decay rates in a memory, in which each        decay rate of the plurality of decay rates is associated with a        respective trading product of the plurality of trading products.

F8. The computer-readable medium of F1, in which the softwareinstructions, when executed by the processor, further cause theprocessor to:

-   -   record at least the reserved quantity of the trading order in an        order book; and        in which reducing the remaining portion of the reserved quantity        by the first quantity comprises:    -   deleting the first quantity from the order book; and in which        reducing the remaining portion of the reserved quantity by the        second quantity comprises:    -   deleting the second quantity from the order book.

G1. An apparatus, comprising:

-   -   a processor; and    -   a memory, in which the memory is communicatively coupled to the        processor, and in which the memory stores software instructions        that, when executed by the processor, cause the processor to:        -   receive, from a trader at a first time, a trading order for            a particular quantity of a trading product, in which a first            portion of the particular quantity is a displayed quantity,            and a second portion of the particular quantity is a            reserved quantity, and in which the trading order specifies            a decay rule;        -   identify the decay rule from the trading order, in which the            decay rule is associated with at least one of the trader and            the trading product, and in which the decay rule specifies            at least a variable decay rate and a time interval;        -   disclose the displayed quantity of the trading order to one            or more market centers;        -   determine that the time interval after the first time has            expired;        -   after determining that the time interval after the first            time has expired, determine that the reserved quantity of            the trading order is greater than zero; and        -   reduce the reserved quantity in accordance with the variable            decay rate without changing the displayed quantity of the            trading order, in which reducing the reserved quantity in            accordance with the variable decay rate comprises;            -   after determining that the time interval after the first                time has expired, reducing the reserved quantity by a                first quantity; and        -   increase the variable decay rate; and        -   after an expiration of a successive time interval after the            time interval, reduce the reserved quantity by a second            quantity, in which the second quantity is larger than the            first quantity.

H1. A method, comprising:

-   -   receiving, from a trader at a first time, by a processor of a        computer, a trading order for a particular quantity of a trading        product, in which a first portion of the particular quantity is        a displayed quantity, and a second portion of the particular        quantity is a reserved quantity, and in which the trading order        specifies a decay rule;    -   identifying, by the processor, the decay rule from the trading        order, in which the decay rule is associated with at least one        of the trader and the trading product, and in which the decay        rule specifies at least a variable decay rate and a time        interval;    -   disclosing, by the processor, the displayed quantity of the        trading order to one or more market centers;    -   determining, by the processor, that the time interval after the        first time has expired;    -   after determining that the time interval after the first time        has expired, determining, by the processor, that the reserved        quantity of the trading order is greater than zero; and    -   reducing, by the processor, the reserved quantity in accordance        with the variable decay rate without changing the displayed        quantity of the trading order, in which reducing the reserved        quantity in accordance with the variable decay rate comprises;        -   after determining that the time interval after the first            time has expired, reducing, by the processor, the reserved            quantity by a first quantity; and    -   increasing, by the processor, the variable decay rate; and    -   after an expiration of a successive time interval after the time        interval, reducing, by the processor, the reserved quantity by a        second quantity, in which the second quantity is larger than the        first quantity.

I1. A computer-readable medium, the computer-readable medium being atangible medium, the computer-readable medium storing softwareinstructions that, when executed by a processor, cause the processor to:

-   -   receive, from a trader at a first time, a trading order for a        particular quantity of a trading product, in which a first        portion of the particular quantity is a displayed quantity, and        a second portion of the particular quantity is a reserved        quantity, and in which the trading order specifies a decay rule;    -   identify the decay rule from the trading order, in which the        decay rule is associated with at least one of the trader and the        trading product, and in which the decay rule specifies at least        a variable decay rate and a time interval;    -   disclose the displayed quantity of the trading order to one or        more market centers;    -   determine that the time interval after the first time has        expired;    -   after determining that the time interval after the first time        has expired, determine that the reserved quantity of the trading        order is greater than zero; and    -   reduce the reserved quantity in accordance with the variable        decay rate without changing the displayed quantity of the        trading order, in which reducing the reserved quantity in        accordance with the variable decay rate comprises;        -   after determining that the time interval after the first            time has expired, reducing the reserved quantity by a first            quantity; and    -   increase the variable decay rate; and    -   after an expiration of a successive time interval after the time        interval, reduce the reserved quantity by a second quantity, in        which the second quantity is larger than the first quantity.

J1. An apparatus, comprising:

-   -   a processor; and    -   a memory, in which the memory is communicatively coupled to the        processor, and in which the memory stores software instructions        that, when executed by the processor, cause the processor to:        -   receive, from a trader at a first time, a trading order for            a particular quantity of a trading product, in which a first            portion of the particular quantity is a displayed quantity,            and a second portion of the particular quantity is a            reserved quantity, and in which the trading order specifies            a decay rule;        -   identify the decay rule from the trading order, in which the            decay rule is associated with at least one of the trader and            the trading product, and in which the decay rule specifies            at least a variable decay rate and a time interval;        -   disclose the displayed quantity of the trading order to one            or more market centers;        -   receive a counterorder for another particular quantity of            the trading product;        -   determine that the counterorder matches the trading order;        -   fill the displayed quantity of the trading order with at            least a portion of the another particular quantity of the            counterorder;        -   determine that the reserved quantity of the trading order is            greater than zero;        -   replenish the displayed quantity of the trading order with a            portion of the reserved quantity of the trading order, in            which a remaining portion of the reserved quantity is left            over after replenishing the displayed quantity;        -   determine that the time interval after the first time has            expired;        -   after determining that the time interval after the first            time has expired, determine that the remaining portion of            the reserved quantity of the trading order is greater than            zero;        -   reduce the remaining portion of the reserved quantity in            accordance with the decay rule, in which any replenishing of            the displayed quantity of the trading order occurs            independently of reducing the remaining portion of the            reserved quantity in accordance with the decay rule, and in            which reducing the remaining portion of the reserved            quantity in accordance with the decay rule comprises:            -   after determining that the time interval after the first                time has expired, reducing the remaining portion of the                reserved quantity by a first quantity; and        -   decreasing the variable decay rate; and        -   after an expiration of a successive time interval after the            time interval, reduce the remaining portion of the reserved            quantity by a second quantity, in which the second quantity            is smaller than the first quantity.

K1. A method, comprising:

-   -   receiving, from a trader at a first time, by a processor of a        computer, a trading order for a particular quantity of a trading        product, in which a first portion of the particular quantity is        a displayed quantity, and a second portion of the particular        quantity is a reserved quantity, and in which the trading order        specifies a decay rule;    -   identifying, by the processor, the decay rule from the trading        order, in which the decay rule is associated with at least one        of the trader and the trading product, and in which the decay        rule specifies at least a variable decay rate and a time        interval;    -   disclosing, by the processor, the displayed quantity of the        trading order to one or more market centers;    -   receiving, by the processor, a counterorder for another        particular quantity of the trading product;    -   determining, by the processor, that the counterorder matches the        trading order;    -   filling, by the processor, the displayed quantity of the trading        order with at least a portion of the another particular quantity        of the counterorder;    -   determining, by the processor, that the reserved quantity of the        trading order is greater than zero;    -   replenishing, by the processor, the displayed quantity of the        trading order with a portion of the reserved quantity of the        trading order, in which a remaining portion of the reserved        quantity is left over after replenishing the displayed quantity;    -   determining, by the processor, that the time interval after the        first time has expired;    -   after determining that the time interval after the first time        has expired, determining, by the processor, that the remaining        portion of the reserved quantity of the trading order is greater        than zero;    -   reducing, by the processor, the remaining portion of the        reserved quantity in accordance with the decay rule, in which        any replenishing of the displayed quantity of the trading order        occurs independently of reducing the remaining portion of the        reserved quantity in accordance with the decay rule, and in        which reducing the remaining portion of the reserved quantity in        accordance with the decay rule comprises:        -   after determining that the time interval after the first            time has expired, reducing, by the processor, the remaining            portion of the reserved quantity by a first quantity; and    -   decreasing, by the processor, the variable decay rate; and    -   after expiration of a successive time interval after the time        interval, reducing, by the processor, the remaining portion of        the reserved quantity by a second quantity, in which the second        quantity is smaller than the first quantity.

L1. A computer-readable medium, the computer-readable medium being atangible medium, the computer-readable medium storing softwareinstructions that, when executed by a processor, cause the processor to:

-   -   receive, from a trader at a first time, a trading order for a        particular quantity of a trading product, in which a first        portion of the particular quantity is a displayed quantity, and        a second portion of the particular quantity is a reserved        quantity, and in which the trading order specifies a decay rule;    -   identify the decay rule from the trading order, in which the        decay rule is associated with at least one of the trader and the        trading product, and in which the decay rule specifies at least        a variable decay rate and a time interval;    -   disclose the displayed quantity of the trading order to one or        more market centers;    -   receive a counterorder for another particular quantity of the        trading product;    -   determine that the counterorder matches the trading order;    -   fill the displayed quantity of the trading order with at least a        portion of the another particular quantity of the counterorder;    -   determine that the reserved quantity of the trading order is        greater than zero;    -   replenish the displayed quantity of the trading order with a        portion of the reserved quantity of the trading order, in which        a remaining portion of the reserved quantity is left over after        replenishing the displayed quantity;    -   determine that the time interval after the first time has        expired;    -   after determining that the time interval after the first time        has expired, determine that the remaining portion of the        reserved quantity of the trading order is greater than zero;    -   reduce the remaining portion of the reserved quantity in        accordance with the decay rule, in which any replenishing of the        displayed quantity of the trading order occurs independently of        reducing the remaining portion of the reserved quantity in        accordance with the decay rule, and in which reducing the        remaining portion of the reserved quantity in accordance with        the decay rule comprises:        -   after determining that the time interval after the first            time has expired, reducing the remaining portion of the            reserved quantity by a first quantity; and    -   decrease the variable decay rate; and    -   after an expiration of a successive time interval after the time        interval, reduce the remaining portion of the reserved quantity        by a second quantity, in which the second quantity is smaller        than the first quantity.

Although the present invention has been described in severalembodiments, a myriad of changes and modifications may be suggested toone skilled in the art, and it is intended that the present inventionencompass such changes and modifications as fall within the scope of thepresent appended claims.

1. An apparatus, comprising: a memory operable to store a trading orderfor a particular quantity of a trading product, in which a first portionof the particular quantity is a displayed quantity, and a second portionof the particular quantity is a reserved quantity; a processorcommunicatively coupled to the memory and operable to: receive thetrading order from a trader; identify a decay rule stored in the tradingorder, in which the decay role is associated with at least one of thetrader and the trading product, and in which the decay rule specifies atleast two of a decay rate, a time interval, and a decay quantity;disclose the displayed quantity of the trading order to one or moremarket centers; receive a counterorder for another particular quantityof the trading product; determine that the counterorder matches thetrading order; fill the displayed quantity of the trading order with atleast a portion of the another particular quantity of the counterorder;determine that the reserved quantity of the trading order is greaterthan zero; replenish the displayed quantity of the trading order with aportion of the reserved quantity of the trading order, in which aremaining portion of the reserved quantity is left over afterreplenishing the displayed quantity; determine that the remainingportion of the reserved quantity of the trading order is greater thanzero; and reduce the remaining portion of the reserved quantity inaccordance with the decay rule, in which any replenishing of thedisplayed quantity of the trading order occurs independently of reducingthe remaining portion of the reserved quantity in accordance with thedecay rule.
 2. The apparatus of claim 1, in which the decay rulespecifies at least the that, upon expiration of each successive timeinterval after the time interval expires, the remaining portion of thereserved quantity diminishes at one of a decreasing rate and anincreasing rate.
 3. The apparatus of claim 1, in which the processor isfurther operable to: upon receiving the trading order from the trader,identify the trader; identify a trader profile associated with thetrader, in which the trader profile is stored in the memory; and updateanother decay role stored in the trader profile based at least in parton The decay rule from the trading order, in which the decay rule isassociated with at least the trader.
 4. The apparatus of claim 1, theprocessor is further operable to: receive, from a second trader, asecond trading order for still another particular quantity of thetrading product, in which the still another particular quantity of thetrading product comprises a second displayed quantity and a secondreserved quantity; and identify a second decay rule stored in the secondtrading order, in which the second decay rule is associated with atleast the second trader and the trading product, and in which the seconddecay rule specifies a second decay rate and at least one of a secondtime interval and a second decay quantity; and cause the second reservedquantity of the second trading order to decay based at least in part onthe second decay rate.
 5. The apparatus of claim 1, in which the decayrule specifies at least the decay rate; in which the decay rate is afirst decay rate and the trading product is a first trading product of aplurality of trading products; and in which the memory is furtheroperable to store a plurality of decay rates, in which each decay rateof the plurality of decay rates is associated with a respective tradingproduct of the plurality of trading products.
 6. The apparatus of claim1, in which the processor is further operable to: record the displayedquantity of the trading order and the reserved quantity of the tradingorder in an order book; and in which the decay role specifies the timeinterval, a second time interval, and the decay rate; and in whichreducing the remaining portion of the reserved quantity in accordancewith the decay rule comprises: in response to an expiration of the timeinterval, deleting a first portion of the reserved quantity from theorder book; and in response to an expiration of the second timeinterval, deleting a second portion of the reserved quantity from theorder book.
 7. The apparatus of claim 1, in which receiving the tradingorder from the trader comprises: receiving the trading order from thetrader at a first time; and in which the processor is further operableto: prior to determining that the remaining portion of the reservedquantity of the trading order is greater than zero, determine that thetime interval after the first time has expired.
 8. The apparatus ofclaim 7, in which the decay role specifies at least the time intervaland the decay quantity; and in which reducing the remaining portion ofthe reserved quantity in accordance with the decay rule comprises: inresponse to determining that the time interval has expired after thefirst time, subtracting the decay quantity from the remaining portion ofthe reserved quantity; and for each successive time interval until theremaining portion of the reserved quantity is zero, in response to anexpiration of the successive time interval, subtracting the decayquantity from the remaining portion of the reserved quantity.
 9. Theapparatus of claim 7, in which the decay rule specifies at least thedecay rate and the time interval, and in which the decay rate is avariable decay rate; and in which reducing the remaining portion of thereserved quantity in accordance with the decay rule comprises: upondetermining that the time interval has expired after the first time,reducing the remaining portion of the reserved quantity by a firstquantity; and in which the processor is further operable to: increasethe variable decay rate; and upon an expiration of a successive timeinterval after the time interval, reduce the remaining portion of thereserved quantity by a second quantity, in which the second quantity islarger than the first quantity.
 10. The apparatus of claim 7, in whichthe decay rule specifies at least the decay rate and the time interval,and in which the decay rate is a variable decay rate; and in whichreducing the remaining portion of the reserved quantity in accordancewith the decay rule comprises: upon determining that the time intervalhas expired after the first time, reducing the remaining portion of thereserved quantity by a first quantity; and in which the processor isfurther operable to: decrease the variable decay rate; and upon anexpiration of a successive time interval after the time interval, reducethe remaining portion of the reserved quantity by a second quantity, inwhich the second quantity is smaller than the first quantity.
 11. Amethod, comprising: receiving, by a processor of a computer, a tradingorder from a trader, in which the trading order is for a particularquantity of a trading product, in which a first portion of theparticular quantity is a displayed quantity, and a second portion of theparticular quantity is a reserved quantity; identifying, by theprocessor, a decay rule stored in the trading order, in which the decayrule is associated with at least one of the trader and the tradingproduct, and in which the decay rule specifies at least two of a decayrate, a time interval, and a decay quantity; disclosing, by theprocessor, the displayed quantity of the trading order to one or moremarket centers; receiving, by the processor, a counterorder for anotherparticular quantity of the trading product; determining, by theprocessor, that the counterorder matches the trading order; filling, bythe processor, the displayed quantity of the trading order with at leasta portion of the another particular quantity of the counterorder;determining, by the processor, that the reserved quantity of the tradingorder is greater than zero; replenishing, by the processor, thedisplayed quantity of the trading order with a portion of the reservedquantity of the trading order, in which a remaining portion of thereserved quantity is left over after replenishing the displayedquantity; determining, by the processor, that the remaining portion ofthe reserved quantity of the trading order is greater than zero; andreducing, by the processor, the remaining portion of the reservedquantity in accordance with the decay role, in which any replenishing ofthe displayed quantity of the trading order occurs independently ofreducing the remaining portion of the reserved quantity in accordancewith the decay rule.
 12. The method of claim 11, in which the decay rulespecifies at least the decay rate and the time interval; and in whichthe decay rate is a variable rate such that, upon expiration of eachsuccessive time interval after the time interval expires, the remainingportion of the reserved quantity diminishes at one of a decreasing rateand an increasing rate.
 13. The method of claim 11, further comprising:upon receiving the trading order from the trader, identifying, by theprocessor, the trader; identifying, by the processor, a trader profileassociated with the trader; and updating, by the processor, anotherdecay rule stored in the trader profile based at least in part on thedecay rule from the trading order, in which the decay rule is associatedwith at least the trader.
 14. The method of claim 11, furthercomprising: receiving, by the processor, from a second trader, a secondtrading order for still another particular quantity of the tradingproduct, in which the still another particular quantity of the tradingproduct comprises a second displayed quantity and a second reservedquantity; identifying, by the processor, a second decay role stored inthe second trading order, in which the second decay rule is associatedwith the second trader and the trading product, and in which the seconddecay rule specifies a second decay rate and at least one of a secondtime interval and a second decay quantity; and causing, by theprocessor, the second reserved quantity of the trading order to decaybased at least in part on the second decay rate.
 15. The method of claim11, in which the decay rule specifies at least the decay rate; in whichthe decay rate is a first decay rate and the trading product is a firsttrading product of a plurality of trading products; and in which themethod further comprises: storing, by the processor, a plurality ofdecay rates, in which each decay rate is associated with a respectivetrading product of the plurality of trading products.
 16. The method ofclaim 11, further comprising: recording, by the processor, the displayedquantity of the trading order and the reserved quantity of the tradingorder in an order book; and in which the decay rule specifies the timeinterval, a second time interval, and the decay rate; and in whichreducing the remaining portion of the reserved quantity in accordancewith the decay rule comprises: in response to an expiration of the timeinterval, deleting, by the processor, a first portion of the reservedquantity from the order book; and in response to an expiration of thesecond time interval, deleting, by the processor, a second portion ofthe reserved quantity from the order book.
 17. The method of claim 11,in which receiving the trading order from the trader comprises:receiving the trading order from the trader at a first time; and inwhich the method further comprises: prior to determining that theremaining portion of the reserved quantity of the trading order isgreater than zero, determine, by the processor, that the time intervalafter the first time has expired.
 18. The method of claim 17, in whichthe decay role specifies at least the time interval and the decayquantity; and in which reducing the remaining portion of the reservedquantity in accordance with the decay rule comprises: in response todetermining that the time interval has expired after the first time,subtracting, by the processor, the decay quantity from the remainingportion of the reserved quantity; and for each successive time intervaluntil the remaining portion of the reserved quantity is zero, inresponse to an expiration of the successive time interval, subtracting,by the processor, the decay quantity from the remaining portion of thereserved quantity.
 19. The method of claim 17, in which the decay rulespecifies at least the decay rate and the time interval, and in whichthe decay rate is a variable decay rate; and in which reducing theremaining portion of the reserved quantity in accordance with the decayrule comprises: upon determining that the time interval has expiredafter the first time, reducing, by the processor, the remaining portionof the reserved quantity by a first quantity; and in which the methodfurther comprises: increasing, by the processor, the variable decayrate; and upon an expiration of a successive time interval after thetime interval, reducing, by the processor, the remaining portion of thereserved quantity by a second quantity, in which the second quantity islarger than the first quantity.
 20. The method of claim 17, in which thedecay rule specifies at least the decay rate and the time interval, andin which the decay rate is a variable decay rate; and in which reducingthe remaining portion of the reserved quantity in accordance with thedecay rule comprises: upon determining that the time interval hasexpired after the first time, reducing, by the processor, the remainingportion of the reserved quantity by a first quantity; and in which themethod further comprises: decreasing, by the processor, the variabledecay rate; and upon an expiration of a successive time interval afterthe time interval, reducing, by the processor, the remaining portion ofthe reserved quantity by a second quantity, in which the second quantityis smaller than the first quantity.
 21. A computer-readable medium, thecomputer-readable medium being a tangible medium, the computer-readablemedium storing software instructions that when executed by a processorcause the processor to: receive a trading order from a trader, in whichthe trading order is for a particular quantity of a trading product, inwhich a first portion of the particular quantity is a displayedquantity, and a second portion of the particular quantity is a reservedquantity; identify a decay rule stored in the trading order, in whichthe decay rule is associated with at least one of the trader and thetrading product, and in which the decay rule specifies at least two of adecay rate, a time interval, and a decay quantity; disclose thedisplayed quantity of the trading order to one or more market centers;receive a counterorder for another particular quantity of the tradingproduct; determine that the counterorder matches the trading order; fillthe displayed quantity of the trading order with at least a portion ofthe another particular quantity of the counterorder; determine that thereserved quantity of the trading order is greater than zero; replenishthe displayed quantity of the trading order with a portion of thereserved quantity of the trading order, in which a remaining portion ofthe reserved quantity is left over after replenishing the displayedquantity; determine that the remaining portion of the reserved quantityof the trading order is greater than zero; and reduce the remainingportion of the reserved quantity in accordance with the decay rule, inwhich any replenishing of the displayed quantity of the trading orderoccurs independently of reducing the remaining portion of the reservedquantity in accordance with the decay rule.
 22. The computer-readablemedium of claim 21, in which the decay role specifies at least the decayrate and the time interval; and in which the decay rate is a variablerate such that, upon expiration of each successive time interval afterthe time interval expires, the remaining portion of the reservedquantity diminishes at one of a decreasing rate and an increasing rate.23. The computer-readable medium of claim 21, in which the softwareinstructions, when executed by the processor, further cause theprocessor to: upon receiving the trading order from the trader, identifythe trader; identify a trader profile associated with the trader; andupdate another decay rule stored in the trader profile based at least inpart on the decay rule from the trading order, in which the decay ruleis associated with at least the trader.
 24. The computer-readable mediumof claim 21, in which the software instructions, when executed by theprocessor, further cause the processor to: receive, from a secondtrader, a second trading order for still another particular quantity ofthe trading product, in which the still another particular quantity ofthe trading product comprises a second displayed quantity and a secondreserved quantity; and identify a second decay rule stored in the secondtrading order, in which the second decay rule is associated with atleast the second trader and the trading product, and in which the seconddecay rule specifies a second decay rate and at least one of a secondtime interval and a second decay quantity; and cause the second reservedquantity of the second trading order to decay based at least in part onthe second decay rate.
 25. The computer-readable medium of claim 21, inwhich the software instructions, when executed by the processor, furthercause the processor to: record the displayed quantity of the tradingorder and the reserved quantity of the trading order in an order book;and in which the decay role specifies the time interval, a second timeinterval, and the decay rate; and in which reducing the remainingportion of the reserved quantity in accordance with the decay rolecomprises: in response to an expiration of the time interval, deleting afirst portion of the reserved quantity from the order book; and inresponse to an expiration of the second time interval, deleting a secondportion of the reserved quantity from the order book.
 26. Thecomputer-readable medium of claim 21, in which receiving the tradingorder from the trader comprises: receiving the trading order from thetrader at a first time; and in which the software instructions, whenexecuted by the processor, further cause the processor to: prior todetermining that the remaining portion of the reserved quantity of thetrading order is greater than zero, determine that the time intervalafter the first time has expired.
 27. The computer-readable medium ofclaim 26, in which the decay role specifies at least the time intervaland the decay quantity; and in which reducing the remaining portion ofthe reserved quantity in accordance with the decay rule comprises: inresponse to determining that the time interval has expired after thefirst time, subtracting the decay quantity from the remaining portion ofthe reserved quantity; and for each successive time interval until theremaining portion of the reserved quantity is zero, in response to anexpiration of the successive time interval, subtracting the decayquantity from the remaining portion of the reserved quantity.
 28. Thecomputer-readable medium of claim 26, in which the decay rule specifiesat least the decay rate and the time interval, and in which the decayrate is a variable decay rate; and in which reducing the remainingportion of the reserved quantity in accordance with the decay rulecomprises: upon determining that the time interval has expired after thefirst time, reducing the remaining portion of the reserved quantity by afirst quantity; and in which the processor is further operable to:increase the variable decay rate; and upon an expiration of a successivetime interval after the time interval, reduce the remaining portion ofthe reserved quantity by a second quantity, in which the second quantityis larger than the first quantity.
 29. The computer-readable medium ofclaim 26, in which the decay rule specifies at least the decay rate andthe time interval, and in which the decay rate is a variable decay rate;and in which reducing the remaining portion of the reserved quantity inaccordance with the decay rule comprises: upon determining that the timeinterval has expired after the first time, reducing the remainingportion of the reserved quantity by a first quantity; and in which theprocessor is further operable to: decrease the variable decay rate; andupon an expiration of a successive time interval after the timeinterval, reduce the remaining portion of the reserved quantity by asecond quantity, in which the second quantity is smaller than the firstquantity.